Receiver, sender, method for retrieving an additional datum from a signal and method for transmitting a datum and an additional datum in a signal

ABSTRACT

A receiver includes a receiver circuit to receive a first transition in a first direction, a second transition in a second, different direction after the first transition and a third transition in the first transition after the second transition of a signal. A first time period between the first and third transitions is indicative of a datum to be received. The receiver circuit is also configured to determine a second time period between the first transition and a second transition and to determine an additional datum to be received based at least on the determined second time period between the first and second transitions. Using the determined second time period allows for more information to be received in a reliable manner.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/933,349 filed on Nov. 5, 2015, which claims priority to GermanApplication No. 10 2014 116 909.3, filed on Nov. 19, 2014, andincorporated herein by reference in its entirety.

FIELD

Embodiments relate to a receiver, a sender, a method for retrieving anadditional datum from a signal, a method for transmitting a datum and anadditional datum in a signal and corresponding computer-, processor- andprogrammable hardware-related implementations.

BACKGROUND

In many fields of technology, data are transmitted from one entity toanother entity using a digital encoding scheme. While in some of theseapplications highly sophisticated transmission schemes are employed, inmany fields a tendency exists to enable a digital transmission using amore simple and yet robust protocol allowing both, a high throughput anda simple implementation. Therefore, a general demand exists to improve atrade-off between robustness of transmission with respect todistortions, simplicity of implementation and a high throughput.

For instance, in the field of high volume architectures using low costimplementations, finding a solution for this trade-off may be morerelevant than in other fields of technology. For instance, in the fieldof communication systems for motorized or non-motorized vehicles,different components including sensors, control units and other devicesoften require a communication architecture allowing a transmission ofdata robust against distortions even under tough operating conditions.Nevertheless, such an architecture should provide enough bandwidth toallow different entities to transmit data. Due to the higher volume ofthese components used in even a single vehicle, a simple and hencecost-efficient implementation may also be important. An example comesfrom the automotive sector, where sensors, control units and otherdevices need to communicate with one another or at least provide data inone direction.

However, also in other fields of technology a comparable demand existsincluding also non-high volume architectures and systems.

SUMMARY

A receiver according to an embodiment comprises a receiver circuit toreceive a first transition in a first direction, a second transition ina second direction after the first transition and a third transition inthe first transition after the second transition of a signal, in which afirst time period between the first and third transitions is at leastpartially indicating a datum to be received. The receiver circuit isconfigured to determine a second time period between the firsttransition and a second transition and to determine an additional datumto be received based at least on the determined second time periodbetween the first and second transitions.

By using a receiver according to an embodiment, the time intervalbetween the first and second transitions may additionally be used totransmit the additional datum, which may lead to a higher throughput ofdata. Moreover, it may be possible to limit the impact on the robustnessof the transition scheme and the simplicity of a correspondingimplementation.

Optionally, the receiver circuit may further be configured to determinethe first time period between the first and third transitions and todetermine the datum based at least on the determined first time period.In other words, the receiver may be capable of determining or retrievingthe datum from the signal.

Optionally, the receiver circuit may be configured to determine thefirst transition and the third transition as transitions from a commonpredefined first signal level to a common predefined second signallevel. This may allow an even more robust transmission of the datum.

Optionally, the receiver circuit may be configured to determine thesecond time period—between the first and second transitions—beingshorter than a minimum period of time after the first transition for atransition to the first level according to a predefined or predeterminedspecification or protocol for transmitting the datum. For instance, itmay be possible to violate a downward compatibility with respect to aprotocol for transmitting the datum, which may allow to even increasethe throughput of data further. However, depending on the robustness ofsuch a legacy implementation, it may be possible for such a receiver tosimply ignore the modification of the second transition. This may allowa downward compatibility.

Additionally or alternatively, in such a receiver the receiver circuitmay be configured to determine the second time period based on thesecond transition to an intermediate signal level different from thefirst signal level and the second signal level. This may further improvea downward compatibility by using the intermediate signal level beingdifferent from the first and second signal levels. Additionally oralternatively, it may allow increasing the bandwidth for the additionaldatum. In such an implementation, the second transition may be atransition, which does not end at the first and second signal levels.The intermediate signal level may be a signal level arranged between thefirst and second signal levels.

Additionally or alternatively, the receiver circuit may be configured todetermine the second time period between the first and secondtransitions based on an amplitude of a second transition. The receivercircuit may further be configured to determine the additional datumbased on at least two different amplitudes of a second transition.Therefore, it may therefore be possible to increase the throughput orbandwidth of the transition scheme even further by additionally allowingthe second transition to comprise different amplitudes to allow thethroughput of data to be increased by using an amplitude modulationscheme additionally.

Naturally, in other embodiments, the receiver circuit may also beconfigured to determine the second time period between the first andsecond transitions based on the second transition always comprising thesame amplitude. This may allow a receiver to be more compatible tolegacy protocols. Additionally or alternatively, this may allow thetransmission protocol to be more robust against distortions since theamplitude does not comprise pieces of information in this case.

Additionally or alternatively, the receiver circuit may be configured todetermine the datum based on the first time period between the first andthird transitions, which is variable and depending on the datum. Inother words, the datum to be received by the receiver is by far notrequired to be constant but may depend on the datum to be transmitted.In yet other words, the signal transmitted may be different from aclassic PWM signal (pulse width modulated signal).

Additionally or alternatively, the receiver circuit may be configured todetermine the datum based on a size of the quantization step of thefirst time period between the first and third transitions being shorterthan or equal to a size of the quantization step of the second timeperiod between the first and second transitions concerning theadditional datum. Due to the first and third transitions beingtransitions in the common first direction, it may be possible to limithardware-related, fabrication-related and/or operation-relatedinfluences on the transitions. This may allow to determine the positionsof the first and third transitions more accurately.

A sender according to an embodiment comprises a sender circuit todetermine, based on a datum to be transmitted, a first time periodbetween a first transition in a first direction and a third transitionin the first direction of a signal to be generated. The sender circuitis further configured to modify, based on an additional datum to betransmitted, a predetermined second time period between the firsttransition and a second transition in a second direction of the signal,when the additional datum is different from a default value. The sendercircuit is further configured to generate the signal comprising thefirst transition in the first direction, the second transition after thefirst transition in the second direction and the third transition afterthe transition in the first direction based on the first and second timeperiods.

Using a sender according to an embodiment may allow improving thepreviously mentioned trade-off between the robustness of thetransmission scheme, the simplicity of a corresponding implementationand a higher throughput of data by using the time period between thefirst and third transitions to transmit the additional datum. Here,based on a predetermined second time period, the sender circuit of thesender may be capable of modifying this second time period, when theadditional datum indicates a corresponding modification.

Optionally, the sender circuit may be configured to generate the signalcomprising the first and third transitions as transitions from a commonpredefined first signal level to a common predefined second level. Asoutlined before, this may further increase the robustness of thetransmission scheme and/or simplify an implementation of the sender.

Optionally, the sender circuit may be configured to modify the secondtime period—between the first transition and the second transition—beingshorter than a minimum period of time after the first transition for atransition to the first level according to a predetermined or predefinedspecification or protocol for transmitting the datum, when theadditional datum indicates the second time period to be shorter than theminimum time. In other words, it may be possible to implement the senderin such a way that it may violate a predefined protocol for transmittingthe datum in order to even increase the data throughput further. Thismay, however, lead to a less compatible sender implementation. However,depending on the robustness of such a legacy implementation, it may bepossible for such a receiver to simply ignore the modification of thesecond transition. This may allow a downward compatibility.

Additionally or alternatively, in such a sender the sender circuit maybe configured to generate the signal comprising the second transition toan intermediate signal level different from the first signal level andthe second signal level. This may further improve a downwardcompatibility by using the intermediate signal level being differentfrom the first and second signal levels. Additionally or alternatively,it may allow increasing the bandwidth for the additional datum. In suchan implementation, the second transition may be a transition, which doesnot end at the first and second signal levels. The intermediate signallevel may be a signal level arranged between the first and second signallevels.

Additionally or alternatively, the sender circuit may be configured tofurther determine an amplitude for the second transition based on theadditional datum from at least two different amplitudes for the secondtransition. The sender circuit may further be configured to generate thesecond transition of the signal with the determined amplitude for thesecond transition. As a consequence, it may be possible to increase thethroughput of data even further by employing an amplitude modulationscheme for sending or transmitting the additional datum. For instance,by implementing the sender circuit to be capable of 2^(n) differentamplitudes, n additional bits for the additional datum could betransmitted. Naturally, also non-2^(n)-multiple state sets of amplitudevalues may be used.

However, in other embodiments, the sender circuit may be configured togenerate the second transition always comprising the same amplitude. Asoutlined, this may improve a compatibility and/or a robustness of thetransmission scheme.

Additionally or alternatively, the sender circuit may be configured todetermine the first time period based on the datum as a variable timeperiod depending on the datum. In other words, the sender may be capableof not only transmitting one fixed piece of information as the datum,but to transmit one of several data by determining the appropriatevariable first time period between the first and third transitions.

Additionally or alternatively, the sender circuit may be configured todetermine the first time period between the first and third transitionsfor the datum based on the size of a quantization step being smallerthan or equal to a size of a quantization step of the second time periodbetween the first and second transitions concerning the additionaldatum. Due to the first and third transitions being transitions in thecommon first direction, it may be possible to limit hardware-related,fabrication-related and/or operation-related influences on thetransitions. This may allow to determine the positions of the first andthird transitions more accurately. A sender according to an embodimentmay, therefore, be used to transmit simultaneously data according to alegacy specification and to transmit an additional datum to a receiveraccording to an embodiment capable of determining the additional datum

Moreover, embodiments also comprise a transceiver comprising a senderand a receiver as described before. In such a case, the sender circuitand the receiver circuit may share common components used for both,sending and receiving the datum and/or the additional datum.

Furthermore, embodiments also comprise a method for retrieving anadditional datum from a signal, wherein the method comprises receiving afirst transition in a first direction, a second transition after thefirst transition and a second direction and a third transition after thesecond transition in the first direction of the signal, in which a firsttime period between the first and third transitions is at leastpartially indicating a datum to be received. The method furthercomprises determining a second time period between the first transitionand the second transition and determining the additional datum to bereceived based at least on the determined second time period.

An embodiment also comprises a method for transmitting a datum and anadditional datum in a signal, wherein the method comprises determining,based on the datum, a first time period between the first transition ina first direction and a third transition in the first direction of thesignal. The method further comprises modifying, based on the additionaldatum, a predetermined second time period between the first transitionand the second transition in a second direction of the signal, when asecond datum is different from a default value. The method alsocomprises generating the signal comprising the first transition in thefirst direction, the second transition after the first transition in thesecond direction and the third transition after the second transition inthe first direction based on the first and second time periods.

Embodiments also comprise a computer program having a program code forperforming any of the methods as described before, when the computerprogram is executed on a computer, a processor or another programmablehardware.

Accordingly, an embodiment may also comprise both, a method forretrieving an additional datum from a signal and a method fortransmitting a datum and an additional datum in a signal as describedbefore. This also applies for the computer program according to anembodiment.

Embodiments further comprise a data transmission system comprising areceiver and a sender, at least one of which is implemented according toan embodiment, as well as a vehicle like a car comprising a control unitcomprising a receiver or a transceiver and at least one sensorcomprising a sender or a transceiver, as described in the context of thecommunication system.

BRIEF DESCRIPTION OF THE DRAWINGS

Several embodiments of the present disclosure will be described in theenclosed Figures.

FIG. 1 shows a simplified block diagram of a data transmission systemaccording to an embodiment;

FIG. 2 illustrates a protocol for transmitting and/or receiving a datum;

FIG. 3 illustrates an asymmetry of a signal with respect to transitionsin a first direction and a second direction;

FIG. 4 illustrates a protocol used by a receiver and/or a senderaccording to an embodiment;

FIG. 5A illustrates a protocol for transmitting and/or receiving adatum;

FIG. 5B illustrates a protocol used by a receiver and/or a senderaccording to an embodiment, in which the second transition comprises adifferent amplitude;

FIG. 6 shows a schematic block diagram of a vehicle comprising a datatransmission system according to an embodiment;

FIG. 7 shows a flowchart of a method for retrieving an additional datumfrom a signal according to an embodiment; and

FIG. 8 shows a flowchart of a method for transmitting a datum and anadditional datum and a signal according to an embodiment.

DETAILED DESCRIPTION

In the following, embodiments according to the present disclosure willbe described in more detail. In this context, summarizing referencesigns will be used to describe several objects simultaneously or todescribe common features, dimensions, characteristics, or the like ofthese objects. The summarizing reference signs are based on theirindividual reference signs. Moreover, objects appearing in severalembodiments or several figures, but which are identical or at leastsimilar in terms of at least some of their functions or structuralfeatures, will be denoted with the same or similar reference signs. Toavoid unnecessary repetitions, parts of the description referring tosuch objects also relate to the corresponding objects of the differentembodiments or the different figures, unless explicitly or—taking thecontext of the description and the figures into account—implicitlystated otherwise. Therefore, similar or related objects may beimplemented with at least some identical or similar features,dimensions, and characteristics, but may be also implemented withdiffering properties.

In many fields of technology, a demand exists to allow components of asystem to transmit data from one component to another using a digitaltransmission scheme. Sometimes, the communication is notuni-directional, but a bi-directional communication allowing an exchangeof data, commands, status information or the like. In the followingdescription information to be transmitted from one component or entityto another component or entity will be referred to as data irrespectiveof the content or the meaning of the respective pieces of information.

In these applications often very different design goals have to be takeninto consideration. However, in many cases, a robust transmission ofdata with respect to distortions, a simple implementation along with ahigh throughput of data represent important design goals. As aconsequence, in many fields of applications a demand exists to improve atrade-off between these parameters.

Examples come, for instance, from high volume and/or low costimplementations, in which technically simple and, hence, cost efficientsolutions may be important. For instance, in the field of components foran intra-vehicle communication, the individual components are oftensubjected to significant distortions while operating under difficultenvironmental influences. For instance, electromagnetic bursts maycouple into electrical or electronic communication systems caused, forinstance, by ignition systems, power control systems or the like.

However, even under these more difficult operational conditions, thecomponents are often required to operate reliably and to be able totransmit and/or receive data with a sufficient high throughput rate toallow the individual components to operate properly and within theirspecified parameters. This may be important, as, for instance,safety-related system and components having a direct influence on thesafety of the passengers of a vehicle may be involved.

An example comes, for instance, from the field of sensors and otherelectronic components of a motorized or non-motorized vehiclecommunicating with one another over the corresponding electrical networkor bus system of the vehicle. Due to the number of different sensorscomprised in a car, a motorcycle or a similar vehicle, the sensors andcontrol units as well as other components are subjected to acorresponding cost pressure, favoring technically more simple solutions.Moreover, a simple solution may be more robust against distortionscompared to more sophisticated protocols and implementations.

However, to limit the number of bus systems or communication systems insuch a vehicle, the corresponding bandwidth or throughput concerningdata to be transmitted via the communication system should besufficiently high to prevent the need to establishing differentcommunication systems. This may allow even to reduce the number ofcommunication systems in such a vehicle.

Although in the example outlined above, a vehicle-related applicationscenario has been described, also in other fields of technology similarproblems exist leading to similar demands. Without the loss ofgenerality, in the following reference will be made to a vehicle-relatedapplication of a communication protocol and its associatedinfrastructure allowing, for instance, a sensor or another component ofa car to communicate with a control unit or a similar other component.

In the following the communication protocol described may be implementedas an electrical communication protocol based on, for instance, anelectrical voltage and/or an electrical current being modulated orchanged to transmit the data. To be a little more specific, in theprotocols described a datum is transmitted or received, which maycomprise in principle any number of different states. However, in thefollowing a bit-based transmission protocol will be described in moredetail, in which a datum may comprise a specified number of bits, whichtranslates into a corresponding number of different states. Forinstance, in the case of a nibble comprising 4 bits, 16 (=2⁴) differentstates may be transmitted. However, the number of bits may be differentin other embodiments. Moreover, it is by far not required to implement abit-based transmission scheme. In principle, any number of statesinstead of a power of 2 (2^(n), n being an integer) may be used.

Examples of corresponding protocols comprise, for instance, SPC (ShortPWM Codes or SENT single-edge nibble transmission). Both of theseprotocols are based on a pulse width modulation (PWM) encoding schemefor the transmission of nibbles or multiples of nibbles, wherein each ofthe nibbles comprises four bits. In these examples the valuation isbased only on falling edges. Although these protocols are comparablyrobust with respect to distortions, an achievable data rate is limitedin the case of both protocols. Both protocols use, however, a quite longperiod in the nibble header, which is not used for data transmission. Aswill laid-out in more detail below, the initial phase of the nibble maybe used to transmit at least one additional bit as an additional datum.

Although in the protocols mentioned only falling edges of the signal areused, in other embodiments also rising edges may be used to transmit adatum. As a consequence, in the following examples of the protocols willbe described in terms of transitions in a first direction and a seconddirection, wherein the second direction is different from the firstdirection. In the case of a SPC implementation or a SENT implementation,the first direction may be a direction associated with a falling edge,while the second direction may be associated with a rising edge. Asmentioned, in other embodiments the roles of falling and arising edgesmay be exchanged.

As will be outlined below, instead of an electric or electronictransmission scheme also other transmission schemes including, forinstance, optical transmission schemes and magnetic transmission schemesmay be used.

FIG. 1 shows a simplified block diagram of a data transmission system100 according to an embodiment. The system 100 comprises a sender 110and a receiver 120, which are coupled via a communication link 130,which may, for instance, comprise a bus for transmitting data at leastin one direction. Naturally, in other embodiments the communication link130 may comprise one or more individual data lines to allow data to betransmitted at least in one direction. Nevertheless, the communicationlink may also be implemented to be capable of transmitting data in bothdirection such that the communication link 130 is a bi-directional linkestablishing a bi-directional communication channel.

The sender 110 and the receiver 120 may be spatially separated fromanother and coupled via the communication link 130. Naturally, thesender 110 as well as the receiver 120 may be a part of a largercomponent for instance, a sensor, an electronic control unit (ECU) or asimilar component of a vehicle such as a car, a truck or anothermotorized or non-motorized vehicle.

The sender 110 comprises a sender circuit 140, while the receiver 120comprises a receiver circuit 150. The communication link 130 may beimplemented as unidirectional communication link allowing data to betransmitted from the sender 110 to a receiver 120. However, instead ofimplementing only a sender 110 and a receiver 120, the two componentsmay further comprise an optional receiver circuit 150′ and an optionalsender circuit 140′, respectively, making the sender 110 and thereceiver 120 transceivers capable of both, sending and receiving data.In this case, the communication link 130 may be implemented as abidirectional communication link allowing exchanging data between thetwo components.

However, although in FIG. 1 the respective sender and receiver circuits140, 150 are shown as distinct blocks, in a real-life implementation,the corresponding circuits may share at least partially components usedfor processing signals and data.

FIG. 2 illustrates an example of a protocol for transmitting a datumfrom a sender 110 to a receiver 120 (not shown in FIG. 2). To be alittle more specific, the protocol depicted in FIG. 2 is based on theSENT standard mentioned before. The protocol is based on a signal 200experiencing transitions in different directions. In the exampledepicted in FIG. 2, the first direction corresponds to a falling edge ofa signal 200, while a transition in the opposite second directioncorresponds to a rising edge. In other examples, the directions may beinterchanged.

The signal 200 comprises a first transition 210 in the first directionhere corresponding to a falling edge of the signal 200. The signal 200further comprises a second transition 220 after the first transition 210in the second direction corresponding here to a rising edge of thesignal 200. After the second transition 220, the signal 200 furthercomprises a third transition 230 again the first direction. As will beoutlined in more detail with respect to the SENT protocol as well as theSPC protocol as one example, a first time period 240 (T_(f2f);f2f=falling to falling edge) between the first and third transitions210, 230 is at least partially indicating a datum to be transmitted orreceived.

Naturally, the signal 200 may further comprise a fourth transition 250bringing the signal 200 back to a common first level 260. The first andthird transitions 210, 230 may be implemented as transitions from thecommon predefined first signal level 260 to a common predefined secondsignal level 270. Depending on the protocol implemented, the differentsignal levels 260, 270 may correspond to different values of a voltage,a potential or a current in the case of an electric or electronic signaltransmission scheme. Naturally, embodiments are by far not limited toelectrical signal transportation, but may also be based on optical,magnetic or other transmission scheme. Depending on the correspondingtransmission scheme, the levels may, for instance, be implemented aspolarization levels, intensity levels in the case of opticaltransmission schemes or as magnetic field strength or magnetic fielddirections in the case of a magnetic transmission scheme.

By implementing a two-level protocol only, the robustness of thetransmission scheme may eventually be better compared to a multi-levelsystem, in which the transitions 210, 220, 230, 250 may assume more thanjust one specified amplitude in the case of a two level transmissionscheme. Accordingly, the receiver circuit 150 of a receiver 120 or acorresponding transceiver may therefore be capable of determining in thefirst time 240 between the first transition 210 and the third transition230 to determine the datum based at least on the determined first timeperiod 240. Correspondingly, the sender circuit 140 may be capable todetermine, based on the datum to be transmitted, the first time period240 between the first transition 210 in the first direction and thirdtransition 230 in the first direction of the signal 200 to be generatedby the sender circuit 140.

In the protocol depicted in FIG. 2, the datum to be transmitted or to bereceived is encoded in the first time period 240, corresponding here tothe time T_(f2f) (falling to falling edge) between the falling edges ofa first and third transitions 210, 230. Between the first and thirdtransitions 230 the second transition 220 in the opposite or seconddirection is located. Between the first transition 210 and the secondtransition 220 in the example depicted in FIG. 2 the signal 200 assumesthe second signal level 270. As a consequence, a second time period 280between the first and second transitions 210, 220 is referred to in FIG.2 as T_(f2r) (falling to rising edge) indicating the time period betweenthe falling edge of the first transition 210 (first direction) to therising edge of the second transition 220 (second direction). However, itshould be noted that the association of the first direction as thefalling edge and the second direction as the rising edge can be easilyswitched in other examples. Moreover, it is by far not required for thesignal to assume only two signal levels 260, 270 as depicted in FIG. 2.

In the example depicted in FIG. 2 the time periods 240, 280 arequantized on a timescale indicated in the lower part of FIG. 2. Here,the timescale is divided into bit times or ticks, which also representthe size of the quantization steps used to determine, for instance, thedatum based on the first time period 240.

In conventional protocols such as the SENT standard or the SPC standardthe low time or second time period 280 is specified to be longer than 4bit times of 4 ticks. In other words, in some of the conventionalstandards the low time separating 2 nibbles is specified to be longerthan four bit times. Naturally, in other specifications that minimum maybe specified to be a different value.

Using the gap between the minimum length of four bit times or ticks andthe last possible location of the second transition 220 (rising edge inFIG. 2), which is needed before the following third transition 230(falling edge in FIG. 2) representing a value of 0 at, for instance, 12bit times or ticks allows to add additional information. As will beoutlined in more detail below, this downtime between the first and thirdtransitions is used to transmit or receive the additional datum.

Depending on the implementation, a downward compatibility with theoriginal standard may or may not be infringed depending on the concreteimplementation. For instance, when the minimum time as indicated aboveis obeyed, a downward compatibility may be upheld, although a legacyreceiver might not be capable of determining the additional datum. Inother words, the downward compatibility is not necessarily infringed inthe case of the original SENT standard, when the minimum time for atransition to the first level 260 is obeyed, since there is norestriction to the length of the initial low time as long as it has morethan 4 bit times. For instance, by introducing a push-pull driver for anoutput of the sender 110, which may be connected to a sensor bus in avehicle to give just one example, may guarantee a maximum length of arising or falling edge of, for instance, 1 bit time or even less.

However, by violating the previously described minimum time for atransition to the first level 260 according to the specification fortransmitting the datum, it may be possible to even transmit moreinformation comprised in the additional datum. For instance, thereceiver circuit may be configured to determine the second time period280 between the first transition 210 and the second transition 220 asbeing shorter than the previously mentioned minimum time for thetransition to the first level 260 according to the specification fortransmitting the datum. Similarly, the sender circuit may be configuredto modify the second time period 280 accordingly, when the additionaldatum to be transmitted indicates the second time period 280 to beshorter than the minimum time of the specification for transmitting thedatum.

In the SENT standard the datum is a nibble comprising exactly four bits.In other words, sixteen different states can be transmitted in the SENTstandard as the datum. Naturally, embodiments are by far not requiredsuch that the datum comprises four bits or a nibble. Different sizes forthe datum may easily be implemented.

The sixteen different states 0, 1, 2, . . . 15 are encoded in the firsttime period 240 as an additional time period corresponding directly tothe number of ticks, which is added to the previously mentioned offsetof 12 bit times or 12 ticks. For instance, the nibble value 0corresponds to the first time period 240 to be 12 ticks long. A nibblevalue of 7 corresponds to 19 bit times or ticks for the first timeperiod 240. Similarly, the value 15 for the nibble corresponds to afirst time period 240 of 27 (=12+15) ticks or bit times.

In other words, the first time period 240 between the first and thirdtransitions 210, 230 is variable and depending on the datum to betransmitted or received. Accordingly, the receiver circuit may beconfigured to determine the datum based on this variable time period.Similarly, the thunder circuit may be configured to determine the firsttime period based on the datum as a variable time period depending onthe datum.

FIG. 2 below the time index the different values of the datum aredepicted below the respective ticks or bit times. Moreover, as dottedlines different third transitions 230 are illustrated, although in FIG.2 for the sake of simplicity only one is marked with the reference sign230. The third transition 230 marked in FIG. 2 corresponds to the nibblevalue 9 at 21 ticks or bit times.

As FIG. 2 illustrates, the protocol used here is an asynchronoustransmission scheme, which does not require a clock signal to betransmitted in parallel. A synchronization and a common time basis maybe established by including a synchronization frame or synchronizationdata to the signal 200.

FIG. 3 shows a schematic diagram of a signal 200 comprising once again afirst transition 210, a second transition 220 and a third transition 230between the first level 260 and a second signal level 270. As outlinedbefore, the first transition 210 and the third transition 230 aretransitions along the first direction, while the second transition 220is a transition in the opposite or second direction.

FIG. 3 however illustrates an effect, which is often encountered inimplementations. The time of the transitions in the first and seconddirections often deviate from one another. For instance, a duration290-1 for a transition in the first direction (here the first transition210) may be shorter than a duration 290-2 for a corresponding transitioninto the opposite, second direction (here second transition 220). Thismay, for instance, be caused by a not fully symmetric implementation ofthe driver circuits of the sender circuit 140 generating the signal 200.For instance, in the SENT standard the maximum fault time is specifiedto be utmost 6.5 μs, while a maximum rise time is 18.0 μs.

Due to this accepted and to some extent even anticipated asymmetry ofthe edges or transitions into the different directions, conventionallytransitions along the same direction are used to determine a datum to betransmitted or received. This may simplify an implementation of thecorresponding sender or receiver circuits 140, 150 since, for instance,signal levels used to determine the presence of a transition lead tomore evenly distribute time differences with respect to the signal 200leaving the starting signal level. In other words, since the first andthird transitions 210, 230 are transitions in the same direction, signallevel used by a concrete receiver circuit 150 to determine the presenceof a transition is assumed more consistently with respect to the pointof time, when the signal 200 leaves the first signal level 260. Usingtransitions along different directions may require additionalcalibration or a more complex implementation, which may be consideredless favorable in view of a simple implementation. However, byimplementing a push-pull-driver in the sender circuit 140 the asymmetrybetween the transitions into the first and second direction may bereduced without a significant increase in terms of the complexity of theimplementation.

FIG. 4 shows a diagram similar to the one depicted in FIG. 2. However,in FIG. 4 the second time period 280 (T_(f2r)) between the first andsecond transitions 210, 220 is also variable and indicative of theadditional datum to be transmitted. To illustrate this, FIG. 4 shows asdashed lines four different transitions along the second direction(rising edge in FIG. 4) from the second signal level 270 to the firstsignal level 260. Here, the second time period Tf2 r indicated in FIG. 4refers to a second transition 220 corresponding to a “limiting” positionof the second transition 220 ensuring in the implementation depicted inFIG. 4 that the following third transition 230 can even safely beimplemented when the datum assumes the value 0 as indicated once againin the lower part of FIG. 4.

However, to be a little more specific, in the examples depicted in FIG.4 the second time period 280 can be varied between four bit times orticks to ten ticks or bit times. Due to a possible asymmetry, which may,however, be limited using corresponding driver technologies for thesender circuit 140, in the examples depicted here a size of thequantization steps for the additional datum is chosen to be 2 ticks or 2bit times. In other words, the size of the quantization steps for theadditional datum are, here, twice as large as the quantization steps forthe datum. In the example depicted in FIG. 4, the working principle ofthis protocol extension uses the rising edge (second transition 220)within the nibble transmission to appear in a time window of 4 to 6, 6to 8 or 8 to 10 ticks or bit times allowing three different values ofthe additional datum to be transmitted. The values are here indicated as0 for the time window 4 to 6 ticks, 1 for the bit times 6 to 8 and 2 forthe bit times 8 to 10. The time windows are assigned to these threedifferent values for the additional transmitted information.

The implementation depicted in FIG. 4 corresponds to a more conservativedesign, taking into account that the rising and falling edges may havedifferent slopes. As a consequence, in this example it is assumed thatthe separation of the symbols may be chosen to be larger than for thestandard time where window of, for instance, the SENT or SPCtransmission scheme, which is defined here by two adjacent fallingedges. This example uses the assumption that the new additional data,which may also be referred to as a sub-nibble, has the same or a bettersignal-to-noise-ratio (SNR) than the standard SENT or SPC nibble.

To retrieve the additional datum, the receiver circuit may be capable ofdetermining the second time period 280 between the first transition 210and the second transition 220 and to determine the additional datumreceived based at least partially on the determined second time period280 between the mentioned transitions 210, 220. Similarly, the sendercircuit 140 of the sender 110 may be capable to modify based on theadditional datum to be transmitted, the predetermined second time period(for instance 10 ticks in the example of FIG. 4) between the firsttransition 210 and the second transition 220 of the signal 200, when theadditional datum is different from a default value (for instance 2 inthe example of FIG. 4) or indicating a corresponding modification.

A sender circuit may then generate the signal 200 based on the firsttime period for the datum and the optionally modified second time period280 for the additional datum. In other embodiments there might be ahigher or lower safety margin for the time measurement. For instance, itmay be advisable to implement the sender 110 and the receiver 120 suchthat the additional datum only comprises a single bit, which may, forinstance, be encoded by associating the value 0 to the bit times orticks 4 to 7 and the value 1 to the bit times or ticks 7 to 10. However,in other embodiments it is by far not required to use integer bit timessince, for instance, the receiver may comprise a microcontroller, whichmay have a much higher time resolution. Similarly, also the sender 110may comprise a similar microcontroller-based circuit allowing a muchfiner resolution. For instance, in the case of a 2 bit comprisingadditional datum the bit times 4 to 5.5 may be assigned to the value 0,the bit times or ticks 5.5 to 7 may be assigned to the value 1, the bittimes or ticks 7 to 8.5 may be assigned to the value 2 and the bit timesor ticks 8.5 to 10 may be assigned to the value 3. Similarly, even morestates may be transmitted as the additional datum. For instance, the bittimes 4 to 5.5 may be associated with the value 0, bit times 5.5 to 7with the value 1, 7 to 8.5 to the value 2, 8.5 to 10 to the value 3, andvalues 10 to 11.5 to the value 4.

In implementations, the quantization step size for the additional datummay be equal to or larger than the corresponding quantization step sizefor the datum. For instance, the quantization of the second time periodmay be chosen to be larger than the one of the first time period, sincethe first period may be measured between transitions in the common firstdirection, such as two falling edges. Thus, these transitions may beless dependent or even independent of hardware parameters, while thesecond period is measured between transitions in opposite directions,for instance, between a falling edge and a rising edge. Thesetransitions may, hence, depend differently on asymmetries, temperaturevariations and supply voltage dependencies of possible pull-up andpull-down drive circuitry and a load setup. In other words, the timeperiod between two transitions in a common direction, such as twofalling edges, may be more precise due to matching than the onebetween—irrespective of the order—a falling and a rising edge, since thetwo edges may have different spreads depending on fabrication parametersand operation conditions.

The size of quantization steps for the additional datum may even besmaller than the size of the quantization steps for the datum. As aconsequence, it may be possible to transmit the additional datumcomprising the same amount of information as the datum or even with ahigher information content. This may additionally be increased by usingan amplitude modulation scheme wherein the receiver circuit 150 and thesender circuit 140 are capable of determining the amplitude of a secondtransition 220 and to determine the additional datum based on thedetermined amplitude of the second transition 220 or generate acorresponding signal 200, respectively. In the case of an amplitudemodulation scheme, the amplitudes may comprise at least two differentamplitudes. However, in distortion rich environments the previouslydescribed implementation of smaller quantization step sizes as well asan amplitude modulation scheme may be less favorable. In such a case itmay, for instance, be more interesting to implement the circuits suchthat the second transition 220 always comprises the same amplitude asthe first transition 210 and/or the third transition 230.

As outlined before the downward compatibility with protocols such asSENT or SPC may be sacrificed such that the additional datum and thecode comprised therein may even start below the previously mentionedfour bit times. Naturally, the additional datum may be used as an errordetection code or an error correction code including, for instance, aredundancy code. In other words, besides increasing the transmitted useddata to other applications, the new data bits of the additional datummay be transmitted to be used as a redundancy code for the followingnibble in, for instance, the SENT protocol or the SPC protocol.Naturally, it may be advisable to use as many receivers 120 as possibleusing the specified extension of this protocol. It may allow an increaseof the data rate due to the shorter bit times made possible.

FIG. 5a illustrates an example of a protocol for transmitting a datumfrom a sender 110 to a receiver 120 (not shown in FIG. 5a ), whichresembles the diagram of FIG. 2. Again, the protocol depicted in FIG. 5ais based on the SENT standard and, hence, illustrates a standard shapeof the PWM signal 200. Here, the second transition 220 brings the signal200 from the second signal level 270 back to the first signal level 260.

FIG. 5b shows an example of a protocol for transmitting not only adatum, but also an additional datum from a sender 110 to a receiver 120(not shown in FIG. 5b ). The signal 200 comprises a first transition210, which transfers the signal level of the signal 200 from the firstsignal level 260 to the second signal level 270, where the signal isconstant for a period of time. The second transition 220 transfers thesignal level from the second signal level 270 to an intermediate signallevel 294. The intermediate signal level 294 may be in between the firstand second signal levels 260, 270 and, for instance, used todifferentiate the signal level used for encoding the additional datumfrom the signal level (first signal level 260) used to encode the datum.

However, in another embodiment, the intermediate signal level 296 may beone signal level used to further increase the available bandwidth byemploying an amplitude-modulation-like technique. A difference betweenthe second signal level 270 and the intermediate signal level 294 may beone amplitude, the sender circuit 140 can choose from, when determiningthe amplitude for the second transition 220 based on the additionaldatum. In this case, a difference between first signal level 260 and thesecond signal level 270 may represent another amplitude the sendercircuit may use to encode the additional datum.

The second transition 220 is followed by a phase with a constant signallevel (intermediate signal level 294), before the signal 200 comprises afurther second transition 296, in the course of which the signal levelis transferred to the first signal level 260. A time period between thefirst transition 210 and the further second transition 296 (T′_(f2r))may also be determined, for instance, to verify timing requirements orother parameters.

Hence, FIG. 5b shows a pulse width modulated signal 200 with differentamplitude.

FIG. 6 shows a schematic block diagram of a possible applicationaccording to an embodiment. This figure shows a vehicle 300 in the formof a car 305 comprising a data transmission system 100 comprising atleast one sensor 310 and an electronic control unit or controller 320.To be a little more specific, the vehicle 300 of FIG. 6 comprises atleast two sensors 310-1, 310-2 which may be wheel speed sensors or othersensors used. The sensors 310 are coupled to the controller 320 via acommunication link 130, which may be implemented as a bus to name justone example. Each of the sensors 310 comprises at least a sender 110 toallow the sensors 310 to provide the controller 320 with sensor data.Accordingly, the controller 320 comprises at least a receiver 120 toallow the data including the additional data sent by the sensors 310 tobe determined. Hence, embodiments may comprise, for instance,SPC-compatible sensor interfaces for transmitting additional informationin the low phase of a signal 200.

FIG. 7 shows a flowchart of a method for retrieving an additional datumfrom a signal 200. The method comprises in a process P100 receiving afirst transition 210 in a first direction, a second transition 220 afterthe first transition 210 in a second direction and a third transition230 after the second transition 220 in the first direction of the signal200. A first time period 240 between the first and third transitions210, 230 is at least partially indicating a datum to be received.

In a process P110, the method further comprises determining a secondtime period 280 between the first transition 210 and the secondtransition 220. In a process P120 the additional datum to be received isdetermined at least partially on the determined second time period 280.

Similarly, FIG. 8 shows a flowchart of a method for retrieving anadditional datum from a signal 200 according to an embodiment. In aprocess P200 a first time period 240 between a first transition 220 in afirst direction and a third transition 230 in the first direction of asignal 200 is determined based on the datum to be transmitted. In aprocess P210 a predetermined second time period between the firsttransition 210 and the second transition 220 in the second direction ofthe signal 200 is modified. This may, for instance, be done, when theadditional datum is different from a default value.

In a process P220 the signal 200 comprising the first transition 210 inthe first direction, the second transition 220 after the firsttransition 210 in the second direction and the third transition 230after the second transition 220 in the first direction is generatedbased on the first and second time periods 240, 280.

Naturally, the order of the processes is by far not restricted to theorder depicted in the figures or the description. The order of executionof the processes may differ in embodiments. Moreover, the processes maybe executed overlapping in time or even simultaneously. They may also berepeated and, for instance, be executed in a loop, until a specifiedcondition is fulfilled.

Naturally, as outlined before, embodiments may also comprise a computerprogram having a program code for performing any of the methoddescribed, when the computer program is executed on a computer, aprocessor or another programmable hardware. Such a programmable hardwaremay, for instance, comprise a controller 230 for a car 305, but also asensor 310 or another device.

The description and drawings merely illustrate the principles of thedisclosure. It will thus be appreciated that those skilled in the artwill be able to devise various arrangements that, although notexplicitly described or shown herein, embody the principles of thedisclosure and are included within its spirit and scope. Furthermore,all examples recited herein are principally intended expressly to beonly for pedagogical purposes to aid the reader in understanding theprinciples of the disclosure and the concepts contributed by theinventor(s) to furthering the art, and are to be construed as beingwithout limitation to such specifically recited examples and conditions.Moreover, all statements herein reciting principles, aspects, andembodiments of the disclosure, as well as specific examples thereof, areintended to encompass equivalents thereof.

Functional blocks denoted as “means for . . . ” (performing a certainfunction) shall be understood as functional blocks comprising circuitrythat is configured for performing or to perform a certain function,respectively. Hence, a “means for s.th.” may as well be understood as a“means being configured or suited for s.th.”. A means being configuredfor performing a certain function does, hence, not imply that such meansnecessarily is performing said function (at a given time instant).

The methods described herein may be implemented as software, forinstance, as a computer program. The sub-processes may be performed bysuch a program by, for instance, writing into a memory location.Similarly, reading or receiving data may b e performed by reading fromthe same or another memory location. A memory location may be a registeror another memory of an appropriate hardware. The functions of thevarious elements shown in the Figures, including any functional blockslabeled as “means”, “means for forming”, “means for determining” etc.,may be provided through the use of dedicated hardware, such as “aformer”, “a determiner”, etc. as well as hardware capable of executingsoftware in association with appropriate software. When provided by aprocessor, the functions may be provided by a single dedicatedprocessor, by a single shared processor, or by a plurality of individualprocessors, some of which may be shared. Moreover, explicit use of theterm “processor” or “controller” should not be construed to referexclusively to hardware capable of executing software, and mayimplicitly include, without limitation, digital signal processor (DSP)hardware, network processor, application specific integrated circuit(ASIC), field programmable gate array (FPGA), read only memory (ROM) forstoring software, random access memory (RAM), and non-volatile storage.Other hardware, conventional and/or custom, may also be included.Similarly, any switches shown in the Figures are conceptual only. Theirfunction may be carried out through the operation of program logic,through dedicated logic, through the interaction of program control anddedicated logic, the particular technique being selectable by theimplementer as more specifically understood from the context.

It should be appreciated by those skilled in the art that any blockdiagrams herein represent conceptual views of illustrative circuitryembodying the principles of the disclosure. Similarly, it will beappreciated that any flow charts, flow diagrams, state transitiondiagrams, pseudo code, and the like represent various processes, whichmay be substantially represented in computer readable medium and soexecuted by a computer or processor, whether or not such computer orprocessor is explicitly shown.

Furthermore, the following claims are hereby incorporated into theDetailed Description, where each claim may stand on its own as aseparate embodiment. While each claim may stand on its own as a separateembodiment, it is to be noted that—although a dependent claim may referin the claims to a specific combination with one or more otherclaims—other embodiments may also include a combination of the dependentclaim with the subject matter of each other dependent claim. Suchcombinations are proposed herein unless it is stated that a specificcombination is not intended. Furthermore, it is intended to include alsofeatures of a claim to any other independent claim even if this claim isnot directly made dependent to the independent claim.

It is further to be noted that methods disclosed in the specification orin the claims may be implemented by a device having means for performingeach of the respective processes of these methods.

Further, it is to be understood that the disclosure of multipleprocesses or functions disclosed in the specification or claims may notbe construed as to be within the specific order. Therefore, thedisclosure of multiple processes or functions will not limit these to aparticular order unless such processes or functions are notinterchangeable for technical reasons.

Furthermore, in some embodiments a single process may include or may bebroken into multiple sub-processes. Such sub-processes may be includedand part of the disclosure of this single process unless explicitlyexcluded.

What is claimed is:
 1. A receiver, comprising: a receiver circuitconfigured to receive a message comprising a plurality of nibbles,wherein at least one of the nibbles comprises a signal waveformcomprising a first transition in a first direction, a second transitionafter the first transition in a second, different direction, and a thirdtransition after the second transition in the first direction of asignal, wherein the receiver circuit is configured to determine a datumassociated with the at least one of the nibbles of the received messagebased at least in part on a first time period between the firsttransition and the third transition, and wherein the receiver circuit isfurther configured to determine an additional datum associated with theat least one of the nibbles of the received message based at least inpart on a second time period between the first transition and the secondtransition.
 2. The receiver according to claim 1, wherein the receivercircuit is further configured to determine the first time period betweenthe first transition and the third transition and to determine the datumbased at least on the determined first time period.
 3. The receiveraccording to claim 2, wherein the receiver circuit is configured todetermine the first transition and the third transition as transitionsfrom a common predefined first signal level to a common predefinedsecond signal level, wherein the common predefined first signal level isgreater than the common predefined second signal level, or the commonpredefined first signal level is less than the common predefined secondsignal level.
 4. The receiver according to claim 3, wherein the receivercircuit is configured to determine the second time period being shorterthan a minimum period of time after the first transition for atransition to the first level according to a single-edge nibbletransmission (SENT) specification or a short PWM codes (SPC)specification for transmitting the datum.
 5. The receiver according toclaim 3, wherein the receiver circuit is configured to determine thesecond time period based on the second transition to an intermediatesignal level different from the first signal level and the second signallevel.
 6. The receiver according to claim 1, wherein the receivercircuit is configured to determine the second time period between thefirst and second transitions based on an amplitude of the secondtransition, and wherein the receiver circuit is configured to determinethe additional datum based on at least two different amplitudes of thesecond transition.
 7. The receiver according to claim 1, wherein thereceiver circuit is configured to determine the second time periodbetween the first and second transitions based on the second transitionalways comprising the same amplitude.
 8. The receiver according to claim1, wherein the receiver circuit is configured to determine the datumbased on the first time period between the first and third transitions,which is variable and depends on the datum.
 9. The receiver according toclaim 1, wherein the receiver circuit is configured to determine thedatum based on a size of a quantization step of the first time periodbetween the first and third transitions being smaller than or equal to asize of a quantization step of the second time period between the firstand second transitions concerning the additional datum.
 10. A sender,comprising: a sender circuit configured to determine, based on a datumto be transmitted, a first time period between a first transition in afirst direction and a third transition in the first direction of asignal portion associated with a single nibble to be generated; whereinthe sender circuit is configured to determine, based on an additionaldatum to be transmitted, a second time period between the firsttransition and a second transition in a second, different direction ofthe signal portion, when the additional datum is different from adefault value; and wherein the sender circuit is further configured togenerate the signal portion comprising the first transition in the firstdirection, the second transition after the first transition in thesecond direction, and the third transition after the second transitionin the first direction based on the determined first and second timeperiods.
 11. The sender according to claim 10, wherein the sendercircuit is configured to generate the signal comprising the first andthird transitions as transitions from a common predefined first signallevel to a common predefined second level, wherein the common predefinedfirst signal level is greater than the common predefined second signallevel, the common predefined first signal level is less than the commonpredefined second signal level.
 12. The sender according to claim 11,wherein the sender circuit is configured to determine the second timeperiod by modifying a predetermined second time period to be shorterthan a minimum period of time after the first transition for atransition to the first level according to a single-edge nibbletransmission (SENT) specification or a short PWM codes (SPC)specification for transmitting the datum, when the additional datumindicates the determined second time period being shorter than theminimum time.
 13. The sender according to claim 11, wherein the sendercircuit is configured to generate the signal portion comprising thesecond transition to an intermediate signal level different from thecommon predefined first signal level and the common predefined secondsignal level.
 14. The sender according to claim 10, wherein the sendercircuit is configured to further determine an amplitude for the secondtransition based on the additional datum from at least two differentamplitudes for the second transition, and wherein the sender circuit isconfigured to generate the second transition of the signal portion withthe determined amplitude for the second transition.
 15. The senderaccording to claim 10, wherein the sender circuit is configured togenerate the second transition always comprising the same amplitude. 16.The sender according to claim 10, wherein the sender circuit isconfigured to determine the first time period as a variable time periodthat is based on a substantive content of the datum.
 17. The senderaccording to claim 10, wherein the sender circuit is configured todetermine the first time period between the first and third transitionsfor the datum based on a size of a quantization step being smaller thanor equal to a size of a quantization step of the second time periodbetween the first and second transitions concerning the additionaldatum.
 18. A method for retrieving a datum and an additional datum froma single nibble portion of a signal, the method comprising: receiving afirst transition of the signal portion in a first direction, a secondtransition of the signal portion after the first transition in a second,different direction and a third transition of the signal portion afterthe second transition in the first direction of the signal portion,wherein a first time period between the first and third transitions ofthe signal portion is at least partially indicative of the datum to bereceived; determining a second time period between the first transitionand the second transition of the signal portion; and determining theadditional datum to be received based at least on the determined secondtime period.
 19. A method for transmitting a datum and an additionaldatum in a single nibble portion of a signal, the method comprising:determining, based on the datum, a first time period between a firsttransition of the signal portion in a first direction and a thirdtransition of the signal portion in the first direction; determining,based on the additional datum, a second time period between the firsttransition of the signal portion and a second transition of the signalportion in a second, different direction, wherein the additional datumis different from a default value; and generating the signal portioncomprising the first transition in the first direction, the secondtransition after the first transition in the second direction, and thethird transition after the second transition in the first directionbased on the determined first and second time periods.
 20. The method ofclaim 19, wherein determining the second time period comprises modifyinga predetermined second time period based on the additional datum.